The present invention relates to electrical connectors and, more particularly, to electrical connectors for interconnecting electrical circuit members such as printed circuit boards, circuit modules, or the like, which may be used in information handling system (computer) or telecommunications environments.
The current trend in design for connectors utilized in high speed electronic systems is to provide high electrical performance, high density and highly reliable connections between various circuit devices, which form important parts of those systems. The system may be a computer, a telecommunications network device, a handheld xe2x80x9cpersonal digital assistantxe2x80x9d, medical equipment, or any other electronic equipment.
One way high electrical performance is manifested is in improved signal integrity. This can be accomplished by providing the interconnections with shielding that helps them to more closely match a desired system impedance. High reliability for such connections is essential due to potential end product failure, should vital misconnections of these devices occur. Further, to assure effective repair, upgrade, and/or replacement of various components of the system (e.g., connectors, cards, chips, boards, modules, etc.), it is also highly desirable that, within the final product, such connections be separable and reconnectable in the field. Such a capability is also desirable during the manufacturing process for such products in order to facilitate testing, for example.
A land grid array (LGA) is an example of such a connection in which each of two primarily parallel circuit elements to be connected has a plurality of contact points, arranged in a linear or two-dimensional array. An array of interconnection elements, known as an interposer, is placed between the two arrays to be connected, and provides the electrical connection between the contact points or pads.
LGA interposers described in the prior art are implemented in many different ways. Many of these were described and compared in one of the referenced copending U.S. patent applications. Compared to the prior art, the inventive LGA carriers described in that referenced patent application significantly improve the reliability of LGA carriers. Another of the referenced copending U.S. patent applications teaches the mechanical and reliability improvement of the carriers through the inclusion of features such as retentive members in openings, and layers of spacers located above and below the planer surfaces of the carriers. But to improve the electrical performance, further invention is necessary.
Yet another referenced copending U.S. patent application teaches that the carriers can be improved electrically such as by metallizing openings, including conductive layers, and further including pairs of shorter length contact members, thereby creating a shielded carrier. The recommendations of materials and processes of the aforementioned patent applications are also important to the improved manufacturability and lower cost of the instant invention.
One way to further enhance the electrical performance and to provide additional functionality to LGA connectors, and particularly to those described hereinabove, is to provide electrical components such as, but not limited to, resistors and capacitors on and/or in the carrier. It is preferable that the components be of the surface mount or of the imbedded variety within the carrier due to the inherent lower profile of these form factors. Depending on the quantity and properties of components in a given application, a carrier with imbedded components may be less expensive to produce.
Decoupling capacitors and terminating resistors are two examples of components that may improve performance. The decoupling capacitors may be used from a signal connection to a reference voltage, or even between reference voltages. A reference voltage is a DC level typically used as a power supply voltage for a given circuit. A circuit may have several difference reference voltages. Some common values are 5.0 volts, 3.3 volts, 3.0 volts, 2.5 volts, 1.8 volts and 0 volts, which is frequently referred to as xe2x80x9cgroundxe2x80x9d. For the case of terminating resistors, not only do they improve the electrical performance of circuits operating at transmission line frequencies, but they save component real estate on the adjacent circuit members. It is only recently that interconnections with high electrical integrity and functionality for use in high speed, high density electronic systems have been required.
The use of surface mount components on printed circuit structures is widely understood. The use of imbedded components within printed circuit structures may not be as well understood. This technology has been implemented by companies such as Ohmega Technologies, Inc. of Culver City, Calif. and Gould Electronics, Inc. of East Lake, Ohio.
U.S. Pat. Nos. 5,530,288 and 5,770,476, both issued to Stone for PASSIVE INTERPOSER INCLUDING ONE PASSIVE ELECTRONIC COMPONENT, have elements that appear similar to those of various embodiments of the invention. However, further study shows significant differences. STONE discloses a printed circuit structure for passive electronic components, including imbedded ones, that are incompatible with fluorocarbon-based (e.g., PTFE) printed circuit boards. The STONE structure is not a connector carrier and cannot support a plurality of contact members for creating an LGA connector as does the present invention.
What has not yet been disclosed is a carrier with components that would result in LGA interposer connectors with improved electrical performance and additional functionality, constituting a significant advancement in the art.
It is, therefore, an object of the invention to enhance the electrical connector art.
It is another object of the invention to provide a carrier for land grid array connectors with components.
It is an additional object of the invention to provide a carrier for land grid array connectors with imbedded components.
The present invention provides a shielded carrier with electrical components, resulting in LGA interposer connectors with improved electrical performance and enhanced functionality. The carrier includes a plurality of components such as, but not limited to, resistors and capacitors on and/or in the carrier. It is preferable that the components be of the surface mount variety or imbedded within the carrier, due to the inherent lower profile of these form factors. Decoupling capacitors and terminating resistors are two examples of components that may improve performance. The decoupling capacitors may be used from a signal connection to a reference voltage, or even between reference voltages. For the case of terminating resistors, not only do they improve the electrical performance of circuits operating at transmission line frequencies, but they also save component real estate on the adjacent circuit members.